Add method to allow elevated privelege operations from Posix

Fazecast · Jan 28, 2022 · bc2ec3e · bc2ec3e
1 parent 28c21ec
commit bc2ec3e
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Showing 2 changed files with 19 additions and 2 deletions.
diff --git a/src/main/c/Posix/PosixHelperFunctions.c b/src/main/c/Posix/PosixHelperFunctions.c
@@ -2,7 +2,7 @@
  * PosixHelperFunctions.c
  *
  *       Created on:  Mar 10, 2015
- *  Last Updated on:  Jan 25, 2022
+ *  Last Updated on:  Jan 28, 2022
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2022 Fazecast, Inc.
@@ -1652,17 +1652,25 @@ int verifyAndSetUserPortGroup(const char *portFile)
 				}
 
 		// Attempt to add the user to the group that owns the port
+		char *addUserToGroupCmd = (char*)malloc(256);
 		if (!userPartOfPortGroup)
 		{
 			struct group *portGroup;
 			struct passwd *userDetails;
 			if ((portGroup = getgrgid(fileStats.st_gid)) && (userDetails = getpwuid(geteuid())))
 			{
-				char *addUserToGroupCmd = (char*)malloc(256);
 				snprintf(addUserToGroupCmd, 256, "sudo usermod -a -G %s %s", portGroup->gr_name, userDetails->pw_name);
 				userCanAccess = (system(addUserToGroupCmd) == 0);
 			}
 		}
+
+		// Attempt to enable all read/write port permissions
+		snprintf(addUserToGroupCmd, 256, "sudo chmod 666 %s", portFile);
+		userCanAccess = (system(addUserToGroupCmd) == 0) || userCanAccess;
+
+		// Clean up memory
+		free(addUserToGroupCmd);
+		free(userGroups);
 	}
 
 	// Return whether the user can currently access the serial port

diff --git a/src/main/c/Posix/SerialPort_Posix.c b/src/main/c/Posix/SerialPort_Posix.c
@@ -65,6 +65,7 @@ jfieldID flowControlField;
 jfieldID sendDeviceQueueSizeField;
 jfieldID receiveDeviceQueueSizeField;
 jfieldID disableExclusiveLockField;
+jfieldID requestElevatedPermissionsField;
 jfieldID rs485ModeField;
 jfieldID rs485ActiveHighField;
 jfieldID rs485EnableTerminationField;
@@ -312,6 +313,8 @@ JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_initializeLibrar
 	if (checkJniError(env, __LINE__ - 1)) return;
 	disableExclusiveLockField = (*env)->GetFieldID(env, serialCommClass, "disableExclusiveLock", "Z");
 	if (checkJniError(env, __LINE__ - 1)) return;
+	requestElevatedPermissionsField = (*env)->GetFieldID(env, serialCommClass, "requestElevatedPermissions", "Z");
+	if (checkJniError(env, __LINE__ - 1)) return;
 	rs485ModeField = (*env)->GetFieldID(env, serialCommClass, "rs485Mode", "Z");
 	if (checkJniError(env, __LINE__ - 1)) return;
 	rs485ActiveHighField = (*env)->GetFieldID(env, serialCommClass, "rs485ActiveHigh", "Z");
@@ -406,6 +409,8 @@ JNIEXPORT jlong JNICALL Java_com_fazecast_jSerialComm_SerialPort_openPortNative(
 	if (checkJniError(env, __LINE__ - 1)) return 0;
 	unsigned char disableExclusiveLock = (*env)->GetBooleanField(env, obj, disableExclusiveLockField);
 	if (checkJniError(env, __LINE__ - 1)) return 0;
+	unsigned char requestElevatedPermissions = (*env)->GetBooleanField(env, obj, requestElevatedPermissionsField);
+	if (checkJniError(env, __LINE__ - 1)) return 0;
 	unsigned char disableAutoConfig = (*env)->GetBooleanField(env, obj, disableConfigField);
 	if (checkJniError(env, __LINE__ - 1)) return 0;
 	unsigned char autoFlushIOBuffers = (*env)->GetBooleanField(env, obj, autoFlushIOBuffersField);
@@ -427,6 +432,10 @@ JNIEXPORT jlong JNICALL Java_com_fazecast_jSerialComm_SerialPort_openPortNative(
 		return 0;
 	}
 
+	// Fix user permissions so that they can open the port, if allowed
+	if (requestElevatedPermissions)
+		verifyAndSetUserPortGroup(portName);
+
 	// Try to open the serial port with read/write access
 	port->errorLineNumber = lastErrorLineNumber = __LINE__ + 1;
 	if ((port->handle = open(portName, O_RDWR | O_NOCTTY | O_NONBLOCK | O_CLOEXEC)) > 0)